Manufacturing method of proton conducting membrane

Abstract

A manufacturing method of a proton conducting membrane includes a pressing process, a hydrolyzing process, and a peeling process. In the pressing process, a resin film is brought into contact with at least one surface of an electrolyte resin material dissolved in polyphosphoric acid and pressure is applied to form the electrolyte resin material into a membrane shape. In the hydrolyzing process, the polyphosphoric acid is hydrolyzed and phosphorylated after the pressing process. In the peeling process, the resin film is peeled off from the electrolyte resin material having the membrane shape after the hydrolyzing process to obtain the proton conducting membrane made of the electrolyte resin material containing phosphoric acid. The resin film is made of a resin having an acidic substituent.

What is claimed is: 
     
         1 . A manufacturing method of a proton conducting membrane, comprising:
 a pressing process of bringing a resin film into contact with at least one surface of an electrolyte resin material dissolved in polyphosphoric acid and applying pressure to form the electrolyte resin material into a membrane shape;   a hydrolyzing process of hydrolyzing and phosphorylating the polyphosphoric acid after the pressing process; and   a peeling process of peeling the resin film from the electrolyte resin material having the membrane shape after the hydrolyzing process to obtain the proton conducting membrane made of the electrolyte resin material containing phosphoric acid, wherein   the resin film is made of a resin having an acidic substituent.   
     
     
         2 . The manufacturing method according to  claim 1 , wherein
 the resin constituting the resin film has at least one type of substituent selected from a group consisting of a carboxyl group, a sulfo group, a hydroxy group, a phosphonic group, and derivatives thereof in at least one of a main chain or a side chain.   
     
     
         3 . The manufacturing method according to  claim 1 , wherein
 in the hydrolyzing process, an environmental humidity is set to be higher than an environmental humidity in the pressing process.   
     
     
         4 . The manufacturing method according to  claim 1 , wherein
 the electrolyte resin material includes a basic resin material having N or NH in a main chain or a side chain, or a resin material having at least one substituent selected from a group consisting of a sulfo group, a carboxyl group, a hydroxy group, a phosphonic group, and derivatives thereof in at least one of a main chain or a side chain.   
     
     
         5 . The manufacturing method according to  claim 4 , wherein
 the electrolyte resin material includes at least one selected from a group consisting of polybenzimidazole, sulfonated polyimide, perfluorosulfonic acid polymer, and derivatives thereof.   
     
     
         6 . The manufacturing method according to  claim 1 , wherein
 the resin film peeled off in the peeling process is reused in the pressing process for manufacturing a next proton conducting membrane.   
     
     
         7 . The manufacturing method according to  claim 1 , wherein
 a concentration of the electrolyte resin material dissolved in the polyphosphoric acid is in a range from 1 wt % to 20 wt %. less.   
     
     
         8 . The manufacturing method according to  claim 1 , wherein
 the proton conducting membrane is formed to have a thickness of 150 μm or less.